1. Field of the Invention
The present invention relates to a simple-to-use ultraviolet radiation (UV) detector, in particular, a portable apparatus that can provide instant feedback of the UV radiation level in an outdoor environment.
2. Description of Related Art
With the advancement of technology and industry, people start to ponder the impact on our environment and us. Without question, the rapid development in high tech industries has provided us with many modern conveniences, but we have also paid a price for these conveniences. For example, the ozone layer used to provide an important function by filters out harmful ultraviolet radiation from the sun. However, scientists discovered that fluorocarbons have caused a hole in the ozone layer in our atmosphere over the Antarctic region. Since ultraviolet radiation is invisible to us, many people have taken the natural protection of the ozone layer for granted. Therefore, the news that the ozone layer is being depleted came as a shock to many people.
In the past, the ozone layer absorbed most of the ultraviolet radiation transmitted to the Earth from the sun, so that only a very small portion get through the atmosphere to the surface of the earth. The potent hazards of UV radiation to living creatures on earth were not very significant, at least not obvious in our daily life.
However, the fact that a part of the ozone layer has been depleted to the extent that a hole exists suggests that the ozone layer surrounding our planet has become thinner. Continued depletion of the ozone layer could cause considerable harm to human beings as well as other living creatures if no action is taken to control the situation. A human body severely exposed to ultraviolet radiation may undergo pathological changes. It is known that some species originally relying on the natural protection against harmful ultraviolet radiation are gradually diminishing. Living creatures on this planet exposed to excessive ultraviolet radiation may be subject to maladies. If the situation is not corrected, some of the species on this planet will be faced with extinction before long.
Destruction of the ozone layer has long been a concern of environmental organizations, and legislation has been enacted to ban the use of ozone-damaging refrigerants in all countries. Despite the legislative efforts all over the world, the hole in the ozone layer has not been mended and is slowly growing in size. If this situation is not corrected, the UV radiation emancipated from the sun through the hole in the ozone layer or the damaged layer is likely to cause skin maladies due to prolonged exposure. Over exposure to UV radiation can cause skin tumors.
Since the excessive exposure to UV radiation has proven to be detrimental to our health, the news media has begun reporting the UV radiation levels in daily weather forecast to provide viewers with some idea of the UV radiation level. However, this kind of forecast information from the news media at best only serves as a general reference. People participating in outdoor activities do not know what precautionary measures to take to protect their skin against UV radiation, because they do not have current information about the UV radiation level in their specification location. Generally, a set of UV detection equipment is very expensive and requires a large space for installation thereby making it impractical for individuals.
Nevertheless, UV radiation is a potent health hazard for those people constantly working in an outdoor environment. It is necessary to produce a simple device that can measure the UV radiation level, and can satisfy consumer needs and be economical at the same time.
The present invention provides a portable apparatus that can be operated with simple procedures to measure the UV radiation level in an outdoor environment. This UV detector includes a main body, a filtering lens, a display module, a printed circuit board, a light detector and multiple batteries.
The main body has an external wall and two ends with a hollow core running through both ends. The filtering lens is mounted on one end of the main body, and a screw plug is mounted on the other end. An enclosed chamber is formed behind the plug to accommodate multiple batteries. A window is formed through the external wall of the main body in which the display module is mounted.
An output conversion circuit on the printed circuit board has an input terminal connected to the light detector mounted underneath the filtering lens and an output terminal connected to the display module mounted in the display panel window in the main body.
The batteries supply the operating voltage for the output conversion circuit and the light detector.
A user of the UV detector only has to orient the filtering lens towards the sky or in the direction of the sun so the light detector can be measure the intensity of light ray. The output conversion circuit converts the measured voltage to a reading scale corresponding to the UV radiation level for display to the user through the display module. Consumers are able to carry the UV detector wherever they go and obtain an instantaneous reading of the UV radiation level in any outdoor environment.
The printed circuit board in accordance with the present invention comprises a push-button switch, a light detection circuit, a comparator circuit and a power switch circuit.
The push-button switch is mounted in a hole appropriately located on the external wall of the main body to control the action of the output conversion circuit and the light detector.
The light detection circuit is composed of multiple resistors and a photo resistor. The resistors form a voltage divider circuit so that a reference voltage is produced at each voltage tapping junction, and the photo resistor is used to form the light detector.
The comparator circuit is formed by multiple comparators. The reference voltage terminal of each comparator is respectively connected to the voltage tapping junction to receive a reference voltage. The input terminal of each comparator is connected to a resistor with a different resistance for voltage detection. The output terminals of these comparators are respectively connected to the corresponding pins of the display module to control the illumination of the lowest display segment on the display module.
The power switch circuit on the printed circuit board is formed by the push-button switch and the batteries in series, adapted to control the operating voltage of the light detection circuit, comparator circuit and display module.
When the push-button switch turns on the battery power, the light detection circuit starts to measure the intensity of incoming light. A measured voltage value is output to the comparator circuit for comparison with the voltage setting values of individual comparators. The result of such comparison is used to determine the number of display segments to be illuminated. The number of display segment illuminated corresponds to the UV radiation level.
Two ends of the push-button switch and the battery in series are connected by a resistor and a Zener diode in parallel at a specified junction. The junction in turn is linked to one of the input pins of the display module to control the illumination of the lowest display segment.
Other objectives, advantages, and novel features of the invention will become apparent from the detailed description when taken in conjunction with the attached drawings.